The invention is concerned with a process and a device for determining the ozone content of ozone-containing gas mixtures according to German patent application P 24 41 857.3-52.
With the above process, the percent range of the ozone content can be continuously determined in a simple and safe manner by use of a stream of the ozone-containing gas mixture channeled over a catalyst of mixed metallic oxides (Hopcalite). The ozone is decomposed to oxygen at the catalyst with the development of heat. The temperature increase between the entering and exiting gas mixture is measured with two thermo-couples which are part of a bridge circuit. The temperature difference which occurs is a measure of the ozone content of the gas mixture.
The continuous measuring of the percent range of the ozone content becomes constantly more important since the charge of ozone grows during water treatment and during the purification of exhuast gas. An accordingly simple and sure or safe measuring process was thereby made possible by the procedures described in the aforesaid German application.
With the process according to the aforesaid application, however, it turned out that the catalyst of mixed metallic oxides becomes contaminated by nitrogen oxides with prolonged use. The nitrogen oxides result, during the production of ozone, from the air, because nitrogen oxides are in part formed in the air. A similar contamination is also sometimes brought about by the available moisture.